Analysis of the dependence of the subthreshold swing and the threshold voltage on the substrate voltage of thin-film SOI MOSFETs: extraction of the interface state densities

The dependence of the subthreshold swing and the threshold voltage on the substrate voltage of thin-film enhancement-mode SOI (silicon-on-insulator) MOSFETs is investigated. The author presents a detailed analysis of the variation of the swing as a function of the substrate voltage by using numerical simulation (the ISIS I program for SOI devices) and an analytical model based on the linearly varying potential (LVP) approximation. Furthermore, the dependence of the threshold voltage on the substrate voltage given by the LVP model is used in combination with the model for the swing in order to extract the interface state densities at the front and back interfaces